He has brought in a host of new faces, including striker Phil Jevons and former Iron defender Jamie McCoombe.
The renewed optimism is reflected in season ticket sales of more than 7,000, and Johnson is confident of ending the side's seven-year absence from the second tier of English football.
He said: "I'm no different from the managers that have stood here before me in saying the aim must be to get Bristol City promoted, but perhaps I am different in that I actually believe it can happen.
"We have the opportunity to reverse the failings of the past regimes. I'm totally aware of the weight of expectation.
"We get 15-20,000 fans at every home game and it's time to reward that terrific support with some long overdue success. Bristol City is ready to take the next step."